Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

The role of colonial ascidians in altering biodiversity in marine fouling communities.

Abstract

Field experiments were conducted at 2 sites with similar species composition in Porthsmouth Harbor, Newcastle, New Hampshire, USA, to study the role of the 3 colonial ascidians (Botrylloides violaceus, Diplosoma listerianum and Didemnum sp.) in the development of fouling communities by comparing the recruitment of species onto panels containing organisms with different functional morphologies. The recruitment of individuals and species was significantly lower on colonial ascidians and sponges compared to erect bryozoans, hydroids, bivalves, sponges, solitary ascidians and encrusting bryozoans. Encrusting byrozoans (Electra pilosa and Membranipora membranacea) and solitary ascidians (Styela clava, Ascidiella aspersa, Ciona intestinalis and Molgula spp.) were found on adult hydroids, bivalves, solitary ascidians and erect bryozoans but not on adult sponges or colonial ascidians. In addition, high numbers of Mytilus edulis, Balanus spp., Molgula spp. and Ectopleura larynx were found on adult hydroids, bivalves, solitary ascidians and erect bryozoans.